bluetooth and leds

Discussion in 'Embedded Systems and Microcontrollers' started by mutzi, Jun 10, 2014.

  1. mutzi

    Thread Starter New Member

    Jun 10, 2014
    3
    0
    Hi,
    I wand to control (say) 100 leds using bluetooth.
    What kind of a controller do i need?

    10x,
    Uri.
     
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    Given your requirements, any controller with a way to communicate with the Bluetooth module and a single I/O pin can control 100 LEDs.

    If, however, you want individual control of each LED, that changes things. If the LEDs are RGB LEDs, that changes things. I think you can see where I'm going here: without specifying your requirements well, you do not limit your choices by any considerable amount.
     
  3. mutzi

    Thread Starter New Member

    Jun 10, 2014
    3
    0
    I see.
    The LEDs are single color, and I need individual control for each LED.
    What is the cheapest controller capable of doing such a thing?

    THANKS!!
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    Odds are that it won't be a single controller that will drive each LED (notice I said drive, not control), meaning that there are ways to control it without using a fast/big/expensive controller.

    Say, for instance, you decide to use 13 cascaded shift registers, then, depending on controls needed for them, you could control 100 LEDs using 3 I/O pins, making a small, 8 pin microcontroller (possibly) more than enough for your application.

    What kind of refresh rate are we talking here? How often do you want all LEDs to be able to respond to a frame/command?

    Again, the longer it takes for you to specify your requirements, the longer and more dragged out this process will be...
     
  5. mutzi

    Thread Starter New Member

    Jun 10, 2014
    3
    0
    tshuck - thank you for the response.
    I was hoping for a refresh rate of (up to) a few seconds.
     
  6. paulfjujo

    New Member

    Mar 6, 2014
    20
    3
    hello,

    if you can have somme mS delay , beetween commande of each groupe, you can
    command 96 leds with 6 MCP23017 on I2C bus ,
    16-Bit I/O Expander with Serial Interface
    each can command 16 outputs
    after maybe you have to add power driver like ULN3008
    because , all output active => 125mA maxi into VDD pin
    <8mA/output


    maxima is 8 expendanders => 128 outputs
     
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